What is H68 brass?
C26000 (Cartridge Brass) emerged from military applications during the industrial revolution, originally developed for ammunition manufacturing. Its 70/30 copper-zinc composition became the benchmark for applications requiring superior deep drawing capabilities and atmospheric corrosion resistance. The alloy gained widespread adoption in North American and European markets, becoming synonymous with high-quality brass applications.
H68 was developed within China's industrial framework as part of the comprehensive GB (Guobiao) standard system. With 68% copper content, it was engineered to provide optimal balance between performance characteristics and material cost, making it particularly suitable for high-volume manufacturing applications. H68 has gained recognition as "the most widely used brass variety" in Chinese industry.
Detailed Chemical Analysis
| Element | C26000 (ASTM B36) | H68 (GB/T 5231) | Difference Impact |
|---|---|---|---|
| Copper (Cu) | 68.5 – 71.5% | 67.0 – 70.0% | C26000: +1.5% average |
| Zinc (Zn) | Balance (28.5-31.5%) | Balance (30.0-33.0%) | H68: +1.5% average |
| Lead (Pb) | ≤ 0.07% | ≤ 0.05% | H68: Tighter control |
| Iron (Fe) | ≤ 0.05% | ≤ 0.10% | H68: More permissive |
| Aluminum (Al) | – | ≤ 0.002% | H68: Specified limit |
| Tin (Sn) | – | ≤ 0.002% | H68: Specified control |
| Antimony (Sb) | – | ≤ 0.005% | H68: Trace element control |
| Arsenic (As) | ≤ 0.02% | – | C26000: Dezincification control |
| Phosphorus (P) | ≤ 0.02% | ≤ 0.002% | H68: Stricter limit |
| Silicon (Si) | – | ≤ 0.007% | H68: Process control |
Microstructural Characteristics
| Property | C26000 | H68 | Significance |
|---|---|---|---|
| Phase Structure | Single α-phase | Single α-phase | Both excellent formability |
| Grain Size (ASTM) | 5-7 | 4-6 | H68: Slightly finer grain |
| Zinc Equivalent | 30.5% | 31.5% | H68: Higher equivalent |
| Phase Stability | Excellent | Excellent | Both stable at room temperature |
| Recrystallization Temp | 300-400°C | 310-420°C | Similar processing windows |
C26000 Advantages from Higher Copper:
Enhanced electrical conductivity (28% IACS vs 26% IACS)
Superior corrosion resistance in atmospheric conditions
Better thermal conductivity for heat transfer applications
Improved brazing and welding characteristics
Enhanced ductility for extreme forming operations
H68 Advantages from Optimized Composition:
Improved strength-to-cost ratio
Better dimensional stability during processing
Enhanced machinability due to refined microstructure
Optimized hot working characteristics
Reduced material cost while maintaining performance
Tensile Properties Comparison
| Condition | Property | C26000 | H68 | Units | Performance Difference |
|---|---|---|---|---|---|
| Annealed (O) | Tensile Strength | 300-380 | 295-375 | MPa | C26000: +5 MPa average |
| Yield Strength (0.2%) | 75-140 | 80-145 | MPa | H68: +5 MPa average | |
| Elongation | 60-68 | 65-70 | % | H68: +3% average | |
| Hardness (HV) | 60-85 | 55-80 | HV | C26000: +5 HV average | |
| Half Hard (H02) | Tensile Strength | 370-450 | 365-445 | MPa | Comparable |
| Yield Strength | 170-275 | 175-280 | MPa | H68: +5 MPa average | |
| Elongation | 25-35 | 28-38 | % | H68: +3% average | |
| Hard (H04) | Tensile Strength | 410-540 | 405-535 | MPa | Comparable |
| Yield Strength | 275-380 | 280-385 | MPa | H68: +5 MPa average | |
| Elongation | 15-25 | 18-28 | % | H68: +3% average |
Fatigue and Endurance Properties
| Test Condition | C26000 | H68 | Units | Application Impact |
|---|---|---|---|---|
| High Cycle Fatigue (10^7) | 140-160 | 145-165 | MPa | H68: Better spring applications |
| Low Cycle Fatigue (10^4) | 280-320 | 285-325 | MPa | Similar performance |
| Rotating Bending | 120-140 | 125-145 | MPa | H68: Slight advantage |
| Axial Fatigue | 100-120 | 105-125 | MPa | H68: Better for rods/bars |
| Corrosion Fatigue | 80-100 | 75-95 | MPa | C26000: Better in corrosive environments |
Temperature-Dependent Mechanical Properties
| Temperature | Property | C26000 | H68 | Performance Notes |
|---|---|---|---|---|
| -40°C | Tensile Strength | 420 MPa | 415 MPa | Both maintain ductility |
| Impact Resistance | High | High | No brittle transition | |
| 20°C | Tensile Strength | 340 MPa | 335 MPa | Reference condition |
| Modulus | 110 GPa | 108 GPa | Similar stiffness | |
| 100°C | Tensile Strength | 315 MPa | 310 MPa | Gradual reduction |
| Creep Resistance | Good | Good | Suitable for moderate temp | |
| 200°C | Tensile Strength | 280 MPa | 275 MPa | Limited applications |
| Oxidation | Moderate | Moderate | Protective atmosphere recommended | |
| 300°C | Tensile Strength | 245 MPa | 240 MPa | Short-term exposure only |
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Our factory
Our factory is equipped with an advanced full-process copper processing production line, specializing in the manufacturing of high-precision copper plates, copper tubes, copper rods, copper wires, and copper strips. The core of our production includes continuous casting and rolling units, precision extrusion lines, high-speed cold rolling equipment, multi-roll precision rolling mills, tube drawing systems, and intelligent stretching production lines. We are also outfitted with comprehensive inspection equipment such as spectrometers and online eddy current flaw detectors, ensuring full-process control from smelting and casting, hot processing, to cold finishing. Our products achieve an accuracy of up to ±0.01mm, with an annual production capacity exceeding 50,000 tons. They are widely used in power, electronics, transportation, and high-end manufacturing sectors. Certified with international standards such as ISO9001 and IATF16949, we are capable of providing global customers with one-stop copper material solutions.
Brass product packaging
We implement a graded and customized packaging system: copper plates are double-wrapped with moisture-proof paper and vapor corrosion inhibitor film before being placed in reinforced wooden crates, which are filled with cushioning materials and equipped with impact-resistant corner protectors; copper tubes and rods are sealed with plastic end caps, wrapped with PE protective film, and then layered into steel-frame logistics containers, with EPE pearl cotton separating each layer; copper wires are automatically wound onto spools, vacuum-sealed, covered with waterproof film, and secured on customized iron-wood pallets; copper strips are wrapped with non-woven fabric, coiled onto high-strength steel cores, and placed into waterproof composite material coils with desiccants inside. All packaging passes ISTA-3A transport testing, and the outer boxes are labeled with international hazardous material identifiers, moisture warnings, and scannable logistics codes, ensuring the cargo withstands moisture, impact, and chemical erosion during global transportation.
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